LOS ANGELES — If "Searching," a mystery about a father looking for his missing teenage daughter told only with smartphone and computer screens, sounds like a gimmick, don't worry, you're in good company. Its star, John Cho, and director and co-writer Aneesh Chaganty thought so too initially. It wasn't even a new concept. The producer for "Searching" was also behind the "screen thriller" ''Unfriended," and wanted a follow-up that used the same technique.

But even with its inauspicious beginnings, the film has become a late summer must-see propelled by strong reviews from critics and a warm afterglow following the successful launch of "Crazy Rich Asians," which has only bolstered enthusiasm around "Searching" and its Asian-American leads.

In its first weekend in limited release, actress Karen Gillan hosted a free screening of the film. "Crazy Rich Asians" director Jon M. Chu and star Henry Golding bought out a theater too. It made an impressive $390,000 from nine theaters and distributor Screen Gems is hoping that momentum continues as it expands to 1,200 screens nationwide this weekend.

Chaganty laughs now about how he was more than willing to walk away from a chance to make his first feature just because he didn't buy into the ploy.

"I like good movies and I want to feel emotional and I don't want to give that up to do something just because there's an opportunity," Chaganty said. "It was a gimmick. I had seen the other films that took place on screens and I thought they were gimmicks."

But he and his co-writer and producing partner Sev Ohanian decided to think about it, and for two months raked their brains for a way in. Then one day, they hit gold. The film, they decided, would open with a montage showing a young family of three through the years told in digital photo albums, videos and calendar dates. It is a slice of life tearjerker that has been compared to the opening of "Up." And, perhaps most importantly, it makes you care about David Kim (Cho) and his daughter Margot (Michelle La).

It's what got Cho on board too, who was put to the test in this role. For the most part, Cho had to act opposite only a blank computer screen and webcam.

"I don't know how I did it, I was bumbling my way through it really," Cho said. "It was weird, it was like acting in a black box ... Several times on set I was like, 'Aneesh can we please stop this webcam business and let's shoot the third act with a bunch of cameras, real cameras and pop out of it? Can we please?'"

According to Cho, Chaganty's response to this was, "John, shut up and act."

While the concept may have been frustrating to execute, however, the final product and story is so seamless it almost makes you forget that you're watching a story unfold through screens.

"After I saw the movie for the first time, I (told Aneesh), 'You have expanded the vocabulary of cinema, and that is so freaking hard to do," Cho said.

"Searching," Cho said, is a kind of bookend to "Crazy Rich Asians" and both are necessary for advancing representation in Hollywood movies.

"That's an Asian specific story and this one isn't," Cho said. "Those are two very important things to say. One is, 'We're going to tell our stories' and the other is, 'Don't limit what our stories are.'"

Chaganty simply wanted an Asian-American lead, and specifically Cho, because those are the families he grew up around in San Jose, California, where the film is set. Other than that, there is no story reason that necessitates that the lead be any ethnicity.

"I grew up watching movies that I loved that had nothing to do with race or culture or addressing skin color that just didn't have people like me in it. 'Mission: Impossible,' the 'Bourne' movies, the ones that don't have anything to do with that," Changanty said. "We've become part of the conversation because we're the first ones to do it in a thriller. It's insane to me that this is even a conversation. I hope people look back on this and are like I don't get how this is racially progressive."

The film's opening and the enthusiasm around it has also made Cho start to reflect on progress. The 46-year-old Korean-American actor's name became its own social media movement in 2016 when a tech savvy man, William Yu, started photoshopping Cho into movie posters for Hollywood blockbusters like "Spectre" along with the hashtag #StarringJohnCho.

"I've been asked so much about it and it's kind of awkward. The common question is, 'Did it work?' And I'm like, 'I don't know!' In a way I was thinking it didn't work because they were like, 'Oh he's supposed to be Captain America' or something in these big tent-pole movies and while I really appreciated that sentiment, I'm not in any of these franchises. I've got my own, but I'm not in any of those," Cho said.

And yet, he also sees a silver lining. The two movies he's starred in since #StarringJohnCho, "Columbus" and "Searching" were directed by Asian-Americans and found their own grassroots success.

"It's an incredible story about what the people can will to be," Cho said.